Hellandite-(Y) Mineral Data

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General Hellandite-(Y) Information

Chemical Formula:

(Ca,REE)4(Y,Ce)2(Al,[ ])2[Si4B4O22](OH)2

Composition:

Molecular Weight = 1,029.47 gm

Calcium 11.68 % Ca 16.34 % CaO

Cerium 6.81 % Ce 7.97 % Ce₂O₃

La,Ce,Pr,Nd,Sm, 13.99 % RE 16.32 % REE₂O₃

Yttrium 12.95 % Y 16.45 % Y₂O₃

Aluminum 1.97 % Al 3.71 % Al₂O₃

Silicon 10.91 % Si 23.35 % SiO₂

Boron 4.20 % B 13.53 % B₂O₃

Hydrogen 0.20 % H 1.75 % H₂O

Oxygen 37.30 % O

______ ______

100.00 % 99.42 % = TOTAL OXIDE

Empirical Formula:

Ca₃REEY_1.5Ce_0.5Al_0.75(Si4B4O22)(OH)₂

Environment:

Pegmatite

IMA Status:

Valid Species (Pre-IMA) 1903

Locality:

Kragero, Telemark, Norway. Link to MinDat.org Location Data.

Name Origin:

Named for Amund Theodor Helland (1846-1918), geologist of Oslo, Norway.

Name Pronunciation:

Hellandite-(Y) + Pronunciation

Synonym:

Hellandite

ICSD 100145

IMA2000-F

PDF 25-184

Hellandite-(Y) Image

Images:

Hellandite-(Y)

Comments: Short-prismatic crystal of dark-brown hellandite-(Y) in granitic pegmatite.
Location: Tusion River Valley, Pamir Mts, Viloyati Mukhtori Gorno-Badakhshan (Viloyati Badakhshoni Kuni), Tajikistan. Scale: FOV is 2x1.7 cm.
© Pavel M. Kartashov

Hellandite-(Y) Crystallography

Axial Ratios:

a:b:c =4.0275:1:2.1845

Cell Dimensions:

a = 18.99, b = 4.715, c = 10.3, Z = 2; beta = 111.4° V = 858.66 Den(Calc)= 3.98

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2/a

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.63(1), 1.89(0.6), 2.82(0.6),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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S - Stereo Pair on/off
H - Help Screen
I - Data Info
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Mellini M , Merlino S , American Mineralogist , 62 (1977) p.89-99, Hellandite: a new type of silicoborate chain

Physical Properties of Hellandite-(Y)

Cleavage:

{001} Poor, {100} Poor

Color:

Green yellow, Grayish black, Reddish brown, Black.

Density:

3.7

Diaphaneity:

Translucent to subtranslucent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

5.5-6 - Knife Blade-Orthoclase

Luminescence:

Non-fluorescent.

Luster:

Vitreous - Greasy

Optical Properties of Hellandite-(Y)

Gladstone-Dale:

CI meas= 0.057 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.123 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1633,KPDmeas= 0.1757,KC= 0.1863
Ncalc = 1.69 - 1.74

Optical Data:

Biaxial (+), a=1.64, b=1.65, g=1.66, bire=0.0200, 2V(Calc)=88, 2V(Meas)=80.

Calculated Properties of Hellandite-(Y)

Electron Density:

Bulk Density (Electron Density)=3.51 gm/cc
note: Specific Gravity of Hellandite-(Y) =3.70 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_{Hellandite-(Y)}= 134.74 barns/electron
U=PE_{Hellandite-(Y)} x r_electron= 472.90 barns/cc.

Radioactivity:

GRapi = 21,088.76 (Gamma Ray American Petroleum Institute Units)
Concentration of Hellandite-(Y) per GRapi unit = 47.42 (PPM)

Hellandite-(Y) is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.

**Estimated Radioactivity from Hellandite-(Y)** - weak
Specimen Size Weight/Volume (Sphere) *	Calculated Activity Becquerels (Bq)	Calculated Activity Curies (Ci)	Estimated Activity GR(api)	Estimated Exposure (mRem**)/hr If Held in Hand For One Hour
1000 gm / 8.02 cm	466,887	1.26E-05	21,088.76	6.93
100 gm / 3.72 cm	46,689	1.26E-06	2,108.88	0.69
10 gm / 1.73 cm	4,669	1.26E-07	210.89	0.07
1 gm / 8.02 mm	467	1.26E-08	21.09	0.01
0.1 gm / 3.72 mm	47	1.26E-09	2.11	0.00
0.01 gm / 1.73 mm	5	1.26E-10	0.21	0.00
0.001 gm / 0.80 mm	0	1.26E-11	0.02	0.00

Weight of pure Hellandite-(Y) in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.70 gm/cc.*
Goverment Estimate of Average Annual Exposure ( 360 mRem) **
Note: 10 microsieverts/hr = 1 mRem/hr **
Max Permissable Adult Dose 50,000 mRem/yr (hands), 15,000 mRem/yr (eyes)
Lethal Dose LD(50) Exposure 400,000 to 500,000 mRem
Estimated Thorium Activity ( 1.04 % Th) From Sum REE Elements (20.79 % REE)

Hellandite-(Y) Classification

Dana Class:

54.02.02.01 (54)Nesosilicate Borosilicates and Some Beryllosilicates

(54.02)with B in [4] coordination

(54.02.02)Hellandite group

54.02.02.01 Hellandite-(Y) (Ca,REE)4(Y,Ce)2(Al,[])2[Si4B4O22](OH)2 P 2/a 2/m

54.02.02.02 Tadzhikite-(Y)! Ca4(Y,Ce)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

54.02.02.03 Tadzhikite-(Ce) Ca4(Ce,Y)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

54.02.02.04 Hellandite-(Ce)! (Ca3REE)4Ce2Al[]2[Si4B4O22](OH)2 P 2/a 2/m

54.02.02.05 Mottanaite-(Ce)! Ca4(Ce,Ca)2AlBe2[Si4B4O22]O2 P 2/a 2/m

54.02.02.06 Ciprianiite! Ca4[(Th,U)(REE)]2(Al,[])2[Si4B4O22](OH,F)2 P 2/a 2/m

54.02.02.07 Piergorite-(Ce)! Ca8Ce2(Al0.5Fe0.5)([],Li,Be)2Si6B8O36(OH,F)2 P 2/a 2/m

Strunz Class:

09.DK.20 09 - SILICATES (Germanates)

09.D - Inosilicates* Structural terminology according to Liebau (1985)

09.DK -Inosilicates with 5-periodic single chains

09.DK.20 Hellandite-(Y) (Ca,REE)4(Y,Ce)2(Al,[])2[Si4B4O22](OH)2 P 2/a 2/m

09.DK.20 Tadzhikite-(Ce) Ca4(Ce,Y)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

09.DK.20 Tadzhikite-(Y)! Ca4(Y,Ce)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

09.DK.20 Ciprianiite! Ca4[(Th,U)(REE)]2(Al,[])2[Si4B4O22](OH,F)2 P 2/a 2/m

09.DK.20 Hellandite-(Ce)! (Ca3REE)4Ce2Al[]2[Si4B4O22](OH)2 P 2/a 2/m

09.DK.20 Mottanaite-(Ce)! Ca4(Ce,Ca)2AlBe2[Si4B4O22]O2 P 2/a 2/m

Other Hellandite-(Y) Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Hellandite-(Y) :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info
12 - Uranium Minerals

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Print or Cut-and-Paste your Hellandite-(Y) Specimen Label here :

Hellandite-(Y)

(Ca,REE)4(Y,Ce)2(Al,[ ])2[Si4B4O22](OH)2
Dana No: 54.02.02.01 Strunz No: 09.DK.20
Locality:

Notes: